Electronic irrigation controllers have long been used on residential and commercial irrigation sites to water turf and landscaping. They typically comprise a plastic housing that encloses circuitry including a processor that executes a watering program. Watering schedules are typically manually entered or selected by a user with pushbutton and/or rotary controls while observing an LCD display. The processor turns a plurality of solenoid actuated valves ON and OFF with solid state switches in accordance with the watering schedules that are carried out by the watering program. The valves deliver water to sprinklers connected by subterranean pipes.
Irrigation controllers are manufactured with a wide range of sizes and features. Large irrigation controllers are typically used in commercial applications, golf courses, playing fields and parks. Large irrigation controllers have the capability of watering many zones, e.g. fifty zones or more, and sometimes have sophisticated features not found in smaller irrigation controllers used in residential applications. For example, large irrigation controllers may have built-in capability for turning sprinklers on and off to optimize the flow of water through the irrigation pipes while meeting the irrigation requirements of the property
The features provided by irrigation controllers continue to evolve to accommodate more complex landscapes and continuously developing strategies to manage water and energy more effectively. Irrigation controllers used in the professional market place tend to be relatively expensive and labor intensive to replace as new feature are introduced. There is a growing need to provide different features on different sites. From a cost standpoint, homeowners and professionals do not want to pay for features they do not require. There is also a need to develop irrigation controllers that meet multiple needs of a landscaped property besides just irrigating plants.
At the present time homeowners and professionals can only purchase irrigation controllers with the capability of adding station modules to increase the number of zones, but without feature upgrade capability. This forces distributors to stock a wide range of irrigation controllers which adds the cost of carrying a large inventory of different types of irrigation controllers. Moreover, as the irrigation needs of a particular landscape site change and/or as government imposes more water usage restrictions, homeowners and professionals are sometimes forced to buy entirely new irrigation controllers.